1. Field of the Invention
Above all, the invention concerns a female contact as well as a plug contact pairing, consisting of plug and socket, with a spark protection according to the preamble to claim 1. The problem with such plug contact pairings is that when plug pin and socket contact are separated, an electric arc that is also called a breaking spark can occur if the contact pairing is separated under load, meaning the circuit is not shut down before plug and socket are separated. Such contact pairings which are separated under load are also referred to as "hot-plug systems." Said systems are used, for example, in computers that supply computer networks as servers. For safety reasons, such servers are provided with so-called "mirrored hard disks," meaning they are provided with two synchronously operating mass storage media. If one of the mass storage media is defective, it does not result in a data loss. Rather, the data still exist on the other mass storage medium, so that the defective storage medium must only be replaced. In order to prevent a standstill of the complete network, such a replacement must be possible under load, so that the computer can continue to operate without a problem during the replacement of the storage medium, that is to say the hard disk.
When separating the plug contact pairings under load, an electric arc called a breaking spark normally occurs from one to the other. This electric arc causes a soldering effect on the contact elements. Material is thus partially removed from the contact elements. The material removed from one contact element can be deposited on the other contact element. Material can thus be removed at the socket contact, which is then deposited on the plug pin. If the plug pin in turn is again fitted into the socket, this removed material can damage the socket and, in the worst case, can lead to a failure of the socket during repeated plugging in, thus causing the plug contact pairing to fail. This destruction of the contacts is especially effective if the roots of the electric arc originate directly at the contact faces.
Placing the socket contacts into conducting spark protection sleeves to alleviate this problem is already known. The conducting spark protection sleeve ensures that the electric arc does not occur between the plug pin and the actual socket contacts, but in the region of the insertion opening for the plug pin on the spark protection sleeve. A material removal at the socket contacts is prevented in this way. Thus, the previously mentioned soldering involving material removal and material deposit occurs only in the region of the electrically conducting spark protection sleeve and the tip of the plug pin. As a result, the contact faces that are positioned opposite each other when plug and socket are connected are not touched by the electric arc.
2. Description of the Related Art
With respect to this, the U.S. Pat. No. 5,591,039 discloses the positioning of a metal ring in front of a contact lamination ring, arranged inside a female contact. This is designed to avoid damage to the contact laminations through electric arc discharges that may occur during the coupling with a contact pin. However, even when using an electrically conducting spark protection sleeve, there is a tendency for the removed material to be deposited in the region of the insertion opening. This material removal or the material deposit, in turn, can either damage the socket pin during the insertion into the insertion opening or can prevent the insertion of the socket pin into this opening completely.
Starting with the described disadvantages, it is the object of the invention to configure a generic female contact or a generic plug contact pairing, such that the deposit of material in the region of the insertion opening is reduced or prevented completely. This object is solved inventively with the combination of features in claim 1.